Electrical interval timer and control



Oct. 16, 1956 F. E. WILLARD ELECTRICAL INTERVAL TIMER AND CONTROL 2 Sheets-Sheet 1 Filed Feb. 21, 1955 mumnom muzca INVENTOR Frank E. Willard ATTORNEYS Oct. 16, 1956 F. E. WILLARD ELECTRICAL INTERVAL TIMER AND CONTROL 2 Sheets-Sheet 2 Filed Feb. 21, 1955 wutaon N s k INVENTOR F ran/r E Willard uuKDOW M u SOk ATTORNEYS United States Patent ELECTRICAL INTERVAL TIMER AND CONTROL Frank E. Willard, Dallas, Tex.

Application February 21, 1955 Serial No. 489,7 ()4 9 Claims. (Cl. 307-132) This invention relates to new and useful improvements in electrical interval timers and controls.

The invent-ion is particularly concerned with devices for rnaking and/or breaking electrical circuits at predetermined intervals with provision for variation of the timing between intervals. The structure is of value for use in conjunction with electrical apparatus, or apparatus subject to electrical control, wherein it is desired to energize a plurality of circuits in sequential order, or to do energize said circuits, to do so at selected intervals, and to have provision for lengthening or shortening said intervals or the timing between the sequential energizations.

It is, therefore, an important object of this invention to provide an improved electrical interval timer which is simple and durable in structure, and which employs standard and inexpensive electrical components.

A particular object of the invention is to provide a device or" the character described which employs multiple contact rotary switches, and in which the electrical circuit through said switches is opened and closed prior to movement of the switch contactor from one terminal to another, whereby the making or breaking of electrical circuits through the rotary switches is avoided and relatively simple and inexpensive types of rotary switches may be employed.

Still another object of the invention is to provide an improved interval timer which opens or closes an electrical circuit at selected intervals, and in which there is provided a unique means for varying or selecting the intervals at which the circuit is opened or closed.

A further object 'of the invention is to provide an improved circuit selecting mechanism which, upon the opening or closing of a control circuit, functions to advance the switch arm of a rotary switch from one circuit terminal to another circuit terminal and which, upon subsequent closing or opening of the control circuit, automatically advances itself into position for subsequent switching operation.

A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention is shown, and wherein:

Fig. l is a diagrammatic view of an interval timer and switching structure constructed in accordance with this invention, and

Figs. 2, 3 and 4 are diagrammatic views of the switching mechanism, illustrating the sequence of operation thereof.

in the drawings, the numeral 10 designates a multiple gang, multi le contact rotary switch of the type having a common operating shaft 11 adapted to be rotated by a pointer or handle 12 overlying a dial or indicator plate 13. In the particular embodiment shown, the multiple switch it? includes four rotary or wafer, multiple contact switches 14, 15, 1e, and 7, respectively. Each of the rotary switches is provided with a switch or wiper arm carried by the operating shah 11 and being numbered 18, 19, 20,

and 21, respectively. Each of the rotary switches is also shown as carrying five terminals or contacts adapted to be engaged by the switch arms as the shaft 11 is rotated, the contacts of switch 14 being numbered 22, the contacts of switch 15 being numbered 23, the contacts of switch 16 being numbered 24, and the contacts of switch 17 being numbered 25. The plate 13 carries time interval indicating indicia 26 with which the pointer 12 is aligned when the switch arms of the rotary switches are engaged with the corresponding terminals of said switches. In the present instance, these intervals are marked for five, ten, fifteen, twenty, and thirty minutes, but obviously, these time intervals are subject to much variation.

Associated with the multiple contact switch 10 is a motor, cam, and multiple contact switch structure 27 which includes a small electrical motor 28 having -a suitable speed reducing connection (not shown) for revolving a shaft 2% at a desired speed. In the present instance, the shaft 29 is caused to undergo one revolution per hour, but obviously, other speeds of revolution, both greater and smaller, may be employed.

The shaft 29 drives a circular cam wheel 36 having a plurality of semi-circular notches 31 in its periphery and engaging the roller arm 32 of a normally open switch 33. As shown in Fig. l, the switch 33 and cam wheel 30 are so arranged as to hold the switch 33 closed except when the roller arm 32 moves downwardly into one of the peripheral notches 31.

The shaft 29 also revolves the contactor arm or plate 34 of a multiple contact switch 35 having a plurality of peripheral contacts 36. In the particular embodiment of the invention illustrated, the switch 35 is provided with eleven of the terminals or contact points 36 arranged in the same spacing and position as the five minute intervals upon the face of a clock with there being no terminal at the sixty minute or twelve oclock position. Similarly, in the particular embodiment illustrated, the cam wheel 38 is provided with twelve of the peripheral notches 31 spaced at equal intervals about the circumference of the cam. Since the shaft 29 is caused to undergo one revolution per hour, it is apparent that the roller arm 32 of the switch 33 will be caused to engage one of the notches 31 each five minutes. Similarly, the wiper arm 34 of the switch 35 will come into engagement with one of the terminals 36 of said switch each five minutes.

The electrical energy controlled and intermitted by this interval timer is supplied from a pair of power leads 37, and normally, will constitute electrical energy at one hundred ten volts, alternating current. The power leads are connected to the motor 28 through a cut-oil switch 38 whereby the motor is driven constantly when the switch is closed. One of the power leads 37 is also connected by a conductor 39 to a power outlet 40, and the other power lead 37 is connected through a conductor 41 to one terminal 42 of the switch 33. Also, by branch conductors 43, the conductor 41 is connected to the wiper arms of each of the rotary switches 14 through 17. The second terminal 44 of the switch 33 is connected by a wire 45 to the other side of the power outlet 40, and also connected by a branch conductor 46 to the wiper arm 34 of the switch 35.

In order to describe the interconnection of the terminals of the rotary switches of the multiple contact switch unit 10 with the terminals of the multiple contact switch 35, the terminals of the former will be identified as the 5, 10, 15, 20, and 30 minute terminals of the corresponding rotary switches, while the terminals of the latter will be described as the one oclock through eleven oclock terminals of the switch 35. It is to be kept in mind, however, that the number of terminals on either of the switches 10 and 35, their relative spacing, and the speed at which the wiper arm 38 is revolved, are all subject to variation and are described herein only with respect to one particular embodiment of the invention.

Referring to Fig. 1, the four oclock and eight oclock terminals of the switch 35 are connected by wires 47 to the fifteen minute terminal of the rotary switch and to the thirty minute terminal of the switch 14. The three oclock and nine oclock terminals of the switch are connected by wires 48 to the ten minute terminal of the switch 16 and the twenty and thirty minute terminals of the switch 15. The two oclock ten oclock terminals of the switch 35 are connected by a wire 4? to the fifteen minute, twenty minute, and thirty minute terminals of the switch 16. The one oclock, five oclock, seven oclock, and eleven oclock terminals of the switch 35 are connected by a wire 50 to the ten minute, fifteen minute, twenty minute, and thirty minute terminals of the switch 17. Further, the six oclock terminal of the switch 35 is connected by a wire 51 to the twenty minute terminal of the switch 14.

Referring to the right-hand portion of Fig. 1, it will be noted that the switch 33 is opened each time the roller arm 32 drops into one of the cam notches 31, and that the circuit to the outlet through the wires 41 and will be broken as the switch 33 is necessarily opened. It will also be noted that there is provided a by-pass or shunt network across or around the switch 33 by means of the conductors leading to the rotary switches of the multiple contactor switch 10, to the terminals of the switch 35 and through the wiper arm 34 and wire 46 to the wire 45. The notches 31 of the cam 39 are so spaced around the periphery of the cam, and the cam and the wiper disk or arm 34 of the switch 35 are so positioned with relation to one another as to bring the arm into engagement with one of the terminals 36 during the time that the roller arm 32 is entering into one of the notches 31 and withdrawing therefrom. Further, the wiper arm 34 has a contact of.

sufiicient width as to cause the same to be in engagement with one of the terminals 36 prior to the time the roller arm begins to enter one of the notches 31 and opens the switch 33. Similarly, the wiper arm rema ns in contact with the terminal the entire length of time the roller arm is engaged within one of the notches 31 and until the roller arm has withdrawn sufficiently from the notch as to close the switch 33 again. Hence, no electrical circuits are opened and closed between the wiper arm 34 and the terminal 36, but rather, all circuits are opened and closed through the switch 33. For this reason, a moderately inexpensive and simple type of rotary, multiple contact switch may be used for the switch 35 Assuming a setting of the arm 12 at the five minute position (the position indicated in Fig. 1) it will be noted that none of the five minute terminals of the switches 14 through 17 are connected to the terminals of the switch 35, and hence, none of the terminals 36 of said switch 35 will be potentialized. Accordingly, the by-pass circuit around the switch 33 remains open at all times, and Whenever the roller arm 32 of the switch 33 drops into one of the notches 31 of the cam wheel 30, this being every five minutes in the embodiment shown, the circuit to the power outlet 40 will be broken. Thus, power will be supplied from the power lead 37 to the power outlet 40 in'five minute intervals with a momentary interruption of the power supply each five minutes.

Assume now the shifting of the wiper arms of the rotary switches 14 through 17 into engagement with the ten minute terminals of said switches, it will be noted that circuits are closed to the wires 43 and which result in the placing of a voltage upon the one oclock, three oclock, five oclock, seven oclock, nine oclock, and eleven oclock terminals of the switch 35. Hence, every other one of the terminals 36 are potentialized, and every other time the roller arm 32 drops into one of the cam notches 31, there will be provided a by-pass circuit to the wire 46 whereby the interruption of the flow of electric current to the power outlet 40 will'be avoided. Hence,

energization of the power outlet in ten minute intervals is achieved.

correspondingly, advancement of the handle or pointer 12 to the fifteen minute, the twenty minute, and the thirty minute positions will potentialize necessary ones of the terminals 36 and result in the supplying of electrical power to the outlet 40 in the selected intervals. In each case, selected ones of the terminals 36 are potentialized so that only those terminals engaged by the wiper arm 34 at the desired intervals are free of an electrical potential. Thus, both the circuits to the power outlet 49 through the switch 33 and the switch 35 are broken or opened only at the selected intervals.

It is quite apparent that any suitable number of the terminals 36 may be employed in the switch 35, that such terminals may be spaced or arranged circumferentially in any desired manner, and that the shaft 29 may be driven at any selected speed. It is necessary that the cam 39 have its notches 31 arranged so as to cause the switch 33 to open as the wiper arm 34 of the switch 35 comes into engagement with each of the terminals 36 in order to place in that particular terminal the control of the circuit to the power outlet 40. Similarly, the rotary switches 14 through 17 may have any desired number of contacts or terminals which may represent any suitable or desirable periods of time. It is further apparent that the normallyopen switch 33 may be replaced by a normally-closed switch connected in series through the wiper arm 34 with the rotary switches v14 through 17, and the wiring between the terminals of the latter switches and the terminals 36 of the switch 35 correspondingly rearranged for supplying to the power outlet 40 momentary, intermittent electrical power at selected intervals, rather than a more or less continuous flow of electrical power momentarily interrupted at selected intervals.

in the embodiment shown, the power outlet 49 is connected to the coil 52 of a relay 52 having its armature 53 connected through a wire 54 to one side of an electrical power source 55. The relay has a normally-closed contact 56 engaged by the armature 53 when the coil 52 is not receiving electric current, and a normally-open contact 57 engaged by the armature 53 when the relay is energized or an electric current is flowing through the coil 52. Thus, when connected into the power outlet 41) of the interval timer described hereinabove, an electric current is applied to the coil 52 through the power outlet 40 a majority of the time, and the relay will be energized a major portion of the time whereby electric power is supplied from the armature 53 to the terminal 57. When the end of a time interval is reached, and the flow of electric current through the power outlet 46 is interrupted, the relay will open, causing the armature to engage the contact 56 and supply electric power thereto for a brief interval of time.

There is provided in conjunction with the relay, an electric motor 58 driving a shaft 59 upon which are mounted the wiper arm or disk 60 of a rotary switch 61, as well as a cam wheel 62. There is also provided on the shaft a suitable handle or pointer 63 overlying an indicating plate 64 having marked thereon at 65 the positions or terminals of the switch 61. For purposes of illustration, the structure is shown diagrammatically, but there is provided, as indicated at 66, means whereby the handle 63 may be revolved independently of the motor 58 or the cam 62 in order to advance the wiper disk 60 of the switch 61.

The disk 60 carries a relatively wide contact element 67 adapted to be brought into engagement with any one of a plurality of circuit terminals 68 arranged circumferentially around the wiper disk. The switch 61 will normally be a simple, commercial type rotary or wafer switch and is illustrated diagrammatically for purposes of simplicity.

An electrical conductor 69 is connected between the V relay contact 57 and the wiper disk or arm 60 for conducting electrical power from the contact 57 to the wiper arm, and in turn to the various circuit terminals 68 of the switch 61.

A dual switch 70 is employed in conjunction with the cam wheel 62 and is provided with a normally-open switch 71 having terminals 72 and 7 3, along with an independent, normally-closed switch 74 having a terminal 75, and sharing the terminal 72 with the switch 71. Both the switches 71 and 74 are operated in unison by a roller arm 76 which engages the periphery of the cam wheel 62 and is adapted to move in and out of the semicircular notches 77 formed in said periphery. Obviously, as the roller arm moves into one of the notches 77, the normally-closed switch will be closed, and the normally-open switch will be open. When the roller arm is not engaged in one of the cam recesses, the normally-open switch is closed, and the normally-closed switch 74 is opened.

The common terminal 72 of the switches 71 and 74 is connected by a wire 78 through the motor 56 to the ground wire 79 of the power source, while the terminal 73 of the normally-open switch 71 is connected through a wire 80 to the contact 56 of the relay. The terminal 75 of the switch 74 is connected by a branch wire 81 to the conductor 69. The ground wire 79 is also connected through the conductor or conductors 82 to the circuits to be controlled, while each of the terminals 68 of the switch 61 is connected individually to said controlled circuits, as indicated at 83. Obviously, the number, arrangement, and order of the terminals 68 so connected to the controlled circuits may be varied as desired.

The operation of this portion of the control unit is illustrated in the left-hand portion of Fig. l and in Figs. 2, 3, and 4. The unit is in running condition in the position illustrated in Fig. l, and electric current is being supplied from the power lead 55 through the wire 54 and the armature 53 to the contact 57, and thence through the wire 6?, wiper disk 60, and through the contact 67 to terminal 1 of the switch 61. Thus, electric current is supplied to a particular controlled circuit between terminal 1 and conductor 82.

In this position of the structure, the motor 58 is not operating since no current is supplied to the contact 56, and since the switch 74 is open. It will be noted that the roller 84 of the roller arm 76 is past full engagement with the cam notch or recess 77 with which it is substantially aligned, and that the cam wheel 62 has advanced sufficiently in a clockwise direction as to lift the roller and the roller arm and actuate the switch 70. Further, the contact 67 of the wiper disk 60, while still in engagement with the terminal 1, has moved sufficiently clockwise as to be almost out of engagement with said terminal.

Now, as the interval timer operates to break the circuit to the power outlet 40 momentarily, the relay coil 52 is de-energized, permitting the armature 53 to move into engagement with the contact 56 and break the circuit to the contact 57, as shown in Fig. 2. As the armature leaves the contact 57, the circuit to the wiper disk 60 is opened and the flow of electric current to terminal 1 of the switch 61 is interrupted. Immediately following this operation, the closing of the armature with the contact 56 supplies electric current through the wire 80 to the terminal 73, and through the switch 71 and the wire 78 to the motor 58 to start the motor operating. The revolution of the motor 58 drives the shaft 59 clockwise to move the contact 67 of the wiper disk 60 from engagement with terminal 1 of the switch 61 into engagement with terminal 2 thereof. It is to be noted that while this shifting of the contact from terminal to terminal of the switch 61 is being carried out, there is no voltage upon the wire 69, and hence no circuits are opened or closed through the contacts or terminals of the switch 61 and arcing or burning of these contacts is eliminated.

The operation of the motor 58 also revolves the cam wheel 62 beneath the roller 84, moving that cam notch 77 in which the roller is engaged in Figs. 1 and 2 from beneath the roller, and moving the next successive cam notch into position wherein the roller may enter thereinto, as shown in Fig. 3.

In the position of the control unit illustrated in Fig. 3, wherein the roller 84 is beginning to enter the next succeeding cam notch 77, the entry of the roller into the cam notch again actuates the dual switch at 70 to close the switch 74 and open the switch 71. The coil 52 of the relay is still not potentialized, and hence, there is no circuit to the motor from the contact 57 of the relay and through the switch 74 to the motor. The circuit to the motor from the potentialized relay contact 56 is broken by the opening of the switch 71, and hence, the motor 58 stops with the contact 67 of the wiper disk 60 having its leading portion in engagement with the terminal 2.

This action takes place very quickly, during the interval the relay coil 52 is not energized, the unit operating to advance the contact 67 almost instantaneously from terminal 1 to terminal 2.

Now, as the relay coil 52 is again energized by the closing of the switch 33, the armature 53 of the relay shifts into engagement with the contact 57, as shown in Fig. 4 and closes a circuit to the motor 58 through the wire 69 to the wire 81 and through the switch 74 and the terminal 72 to the wire 78, and thence to the motor. Thus, the motor is again actuated for a brief interval and revolves the shaft 59 to drive the cam wheel 62 and the Wiper disk 68 in a clockwise direction. This operation shifts the contact 67 of the disk 60 with respect to the terminal 2 and brings the trailing portion of the contact into alignment with terminal 2 in the same position as shown for terminal 1 in Fig. 1. At the same time, the cam is further advanced into the position shown in Fig. 1 wherein the switch 74 is again opened, breaking the circuit to the motor 58 and stopping the same. The switch 71 is closed by this movement, but since the armature 5'3 is not in engagement with the contact 56, no circuit is completed to the motor 58. Instead, the unit is brought into position or condition for immediate and almost instantaneous shifting of the contact 67 to the next of the terminals 68 upon the next succeeding de-energization of the relay coil 52.

It is pointed out that the switch 61 may be independently operated by manual rotation of the handle 63, and that thereafter, the unit will continue to operate automatically, shifting to the next circuit represented by the next succeeding terminal 68 upon actuation by the interval timer. It is also pointed out that the terminals 68 may be evenly spaced around the switch 61 whereby the unit will operate continuously and recycle indefinitely through each of the terminals in successive order. In the particular embodiment illustrated, the uppermost terminal, represented by the twelve oclock position of the switch 61, is omitted.

Obviously, the two power sources may be combined, other conventional electrical components or switches may be mounted upon either or both of the shafts 29 and 59 for limiting operation of the unit to a single cycle or a predetermined number of cycles, and other obvious or expedient modifications may be made. The switch 61 may be a multiple switch unit and may selectively open or close any number of circuits in a predetermined order and at varying or uniform intervals, depending upon the setting and arrangement of the interval timer shown in the right-hand portion of Fig. l.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. An electrical circuit control device including, a switch, means for opening the switch at timed intervals, a shunt circuit across the switch, and means for closing the shunt circuit in synchronization with selected ones of the timed intervals.

2. An electrical circuit control device including, a switch, means for opening the switch at timed intervals, a shunt circuit across the switch, and means for closing the shunt circuit slightly in advance of selected ones of the switch openings and opening the shunt circuit shortly after the re-closing of the switch.

3. An electrical circuit control device including, a switch, means for actuating the switch at timed intervals, a plurality of shunt circuits, means for connecting each of the shunt circuits sequentially in timed order to one side of the switch in synchronization with the switch actuations, and means for connecting selected ones of the shunt circuits to the other side of the switch.

4. An electrical circuit control device including, a cam-actuated switch, a cam for actuating the switch at timed intervals, a motor for driving the cam, a rotary switch driven by the motor and having a rotating switch arm and a plurality of terminals engaged sequentially by the switch arm in synchronization with the actuation of the cam-actuated switch, a plurality of shunt circuits connected to one side of the cam-actuated switch, and means for connecting selected ones of the shunt circuits to the other side of the cam-actuated switch.

5. An electrical circuit control device including, a camactuated switch, a cam for actuating the switch at timed intervals, a motor for driving the cam, a rotary switch driven by the motor and having a rotating switch arm and a plurality of terminals engaged sequentially by the switch arm in synchronization with the actuation of the cam-actuated switch, the cam-actuated switch including a normally-open switch which is closed when the camactuated switch is actuated and a normally-closed switch which is opened when the cam-actuated switch is actuated, a first power circuit connected to the motor through the normally-open switch, a second power circuit connected to the motor through the normally-closed switch, means .for supplying electrical power alternately to the first and second power circuits, and the cam and rotary switch being aligned whereby the cam actuates the cam-actuated switch only when the switch arm of the rotary switch is in engagement with one of the terminals thereof.

6. An electrical circuit control device as set forth in claim 5, wherein the means for supplying electrical power alternately to the first and second power circuits includes, a switch, means for opening the switch at timed intervals, a shunt circuit across the switch, and means for closing the shunt circuit at timed intervals in synchronization with the opening of the switch.

7. An electrical circuit control device as set forth in claim 5, wherein the means for supplying electrical power alternately to the first and second power circuits includes, a switch, means for opening the switch at timed intervals, a shunt circuit across the switch, and means for closing the shunt circuit slightly in advance of selected ones of the switch openings and opening the shunt circuit shortly after the re-closing of the switch.

8. An electrical circuit control device as set forth in claim 5, wherein the means for supplying electrical power alternately to the first and second power circuits includes, a switch, means for actuating the switch at timed intervals, a plurality of shunt circuits, means for connecting each of the shunt circuits sequentially in timed order to one side of the switch in synchronization with the switch actuations, and means for connecting selected ones of the shunt circuits to the other side of the switch.

9. An electrical circuit control device as set forth in claim 5, wherein the means for supplying electrical power alternately to the first and second power circuits includes, a cam-actuated switch, a cam for actuating the switch at timed intervals, a motor for driving the cam, a rotary switch driven by the motor and having a rotating switch arm and a plurality of terminals engaged sequentially by the switch arm in synchronization with the actuation of the cam-actuated switch, a plurality of shunt circuits connected to the rotary switch terminals, the switch arm being connected to one side of the cam-actuated switch, and means for connecting selected ones of the shunt circuits to the other side of the cam-actuated switch.

References Cited in the file of this patent UNITED STATES PATENTS 

